K31 serial numbers and manufacturing dates

K31 modifications history

1934

The firing pin was lightened.

1935

The receiver was made from hardened steel.

1936

The magazine was made from hardened steel.

1941

Stocks made from laminated plywood were tested, but rejected.

1944

Due to supply shortages, Chromium Molybdenum Steel was use in place of Chromium Nickel Steel on various parts. (Recognisable by “+CM” markings instead of the usual “+CN” markings) This experiment proved unsuccessful.

1946

Starting with K31 serial number 868,901, beech wood rather than walnut wood was used for making the stocks.

Serial numbers and manufacturing dates

Swiss Schmidt-Rubin rifles do not have the date of manufacture stamped on any of the rifle parts, so determining when the rifle (and mismatched parts, if any) were manufactured must be determined from the serial numbers. The definitive work on this subject, and Schmidt-Rubin rifles in general, is Die Repetiergewehre der Schweiz, Die Systeme Vetterli und Schmidt-Rubin, by Reinhart, Sallaz, and am Rhyn (ISBN 3-7276-7102-5, copyright 1991 by Verlag Stocker-Schmid AG, Dietikon-Zuerich, Schweiz), from which the tables given here are adapted.